Plasma-assisted wafer processing is a process established sufficiently in the production of a semiconductor device which is usually called an integrated circuit. Conventionally, there are numerous different plasma-assisted processes such as etching, sputtering deposition, and chemical phase deposition. All of these processes must be performed so as to realize a uniform etching speed or a uniform processing speed on a wafer surface. If a non-uniform processing speed occurs on the wafer surface, the semiconductor device is produced as having numerous defects.
In the following, a conventional technique will be described specifically with reference to a conventional plasma processing apparatus 800 shown in FIG. 8. In the plasma processing apparatus 800, a chamber 201 provided on the air side of a target electrode 2 (first electrode) is configured with an upper wall (ceiling wall) 202, a cylindrical side wall 203, and a bottom wall 204. An upper electrode high-frequency power source 102 supplies high-frequency power to an upper electrode 1 via an upper electrode matching device 101. A lower electrode 301 is configured with a stage holder 302 and a lower electrode insulator 303. A lower electrode high-frequency power source 305 supplies high-frequency power to the lower electrode 301 via a lower electrode matching device 304. The gas within the chamber 201 is exhausted via a gas exhaust port 205. A magnetic mechanism having a point-cusp magnetic field forms a divergent magnetic field in the outer peripheral part of the target electrode 2 (first electrode). Thereby, the plasma density on the surface of the target electrode 2 (first electrode) becomes different between the center part and the outer peripheral part of the target electrode 2 (first electrode) and the film deposition rate becomes non-uniform on the wafer 306. Patent document 1 discloses an invention which mounts a magnet mechanism 5 (configured with a magnet 6 and a plate body 7) which arranges magnets 6 in a range wider than the diameter of the target electrode 2 (first electrode) for not allowing the divergent magnetic field to be formed on the surface of the target electrode 2 (first electrode), and causes the film deposition rate on the wafer 306 to become uniform across the surface by making the plasma density on the surface of the target electrode 2 (first electrode) to be the same between the center part and the peripheral part of the target electrode 2 (first electrode).
FIG. 9 is a plan view showing a magnet arrangement pattern above the upper electrode 1 when viewed from the upper side or the lower side. FIG. 9 shows an X axis and a Y axis, and also shows numerous small circles each showing the end surface of the magnet 6. Each of the characters of N and S indicates magnetic polarity of the magnet 6 when viewed from the lower side. Each of the magnets 6 is arranged so as to have an opposite polarity to another magnet 6 neighboring in X axis or Y axis direction and also to have the same polarity as another magnet 6 neighboring in a diagonal line (e.g., straight line a, b, c or d) of a rectangle formed by any four magnets 6. An insulating member 4 is disposed so as to surround the numerous magnets 6.
Patent document: Japanese Unexamined Patent Application Publication No. 2003-318165
When using such a conventional plasma processing apparatus for a sputtering process, it is necessary to provide a shield 3 on the insulating member 4 and the target electrode 2 (first electrode) for preventing film adhesion. In the conventional plasma processing apparatus, however, there has been a problem that the shield 3, the target electrode 2 (first electrode), or the insulating member 4 is damaged and thereby an unstable processing is caused. Any means solving these problems have not been known as far as the present inventor knows.